Resistivity measurements of layered metallic films at various microwave frequencies and temperatures using the micro-strip T-junction method

The frequency and temperature dependence of the surface resistance of metallic films was measured by a microwave micro-strip method under a T-junction structure. Numerical analysis of micro-strips made of silver-tin (Ag-Sn) alloy, or good conducting niobium (Nb) films reveals the surface resistances behaving as nearly a one-half power law dependence on the frequency, which is in congruence with the results derived from the free-electron model in simple metals. In addition, we have specifically investigated the electron transport with a strong localization effect on the DC temperature-dependent resistivity in abnormal and normal Nb films. The results indicate a deviation from a one-half power law may occur in the abnormal film. This work can be further exploited to measure the conductivity and penetration depth of metals in multilayered structure or of superconducting films.